1. Field of the Invention
This invention relates to a data recoding apparatus that can record data signals on a magnetic recording medium such as a magnetic tape and, a data recording method.
2. Description of Related Art
Magnetic tape, which is one example of a magnetic recording medium, has various applications such as audio tape, video tape, and computer tape, although particularly in the field of tapes for data backup, magnetic tapes with a storage capacity of several hundred GB per reel have been commercialized, following the increase in the capacity of hard disks for data backup. From now on, making backup tapes higher in capacity is essential for further increases in the capacity of hard disks.
It is possible to record data signals on a magnetic tape by magnetizing the magnetic layer of a magnetic tape in a first magnetized direction or a second magnetized direction, which is in the opposite direction. Using the conventional recording apparatus shown in FIG. 3, a recording current +Iw is input to the input terminal 103 and a recording current −Iw, which is in opposite phase to the recording current +Iw, is input to the input terminal 104. The transistors 102a and 102b become ON for the period when the recording current +Iw, which is input to the input terminal 103, is High, and the head 101 operates so as to magnetize the magnetic tape in the first magnetization direction. Next, the transistors 102c and 102d become ON when the recording current −Iw, which is input to the input terminal 104, is High. The head 101 operates so as to magnetize the magnetic tape in the second magnetization direction. In this way, by switching in order the direction of the current that flows onto the head 101, it is possible to magnetize the magnetic tape in the first or second magnetization direction.
In FIG. 4, the schematic view (a) shows the magnetizing conditions for a magnetic tape before data signal recording. The region 111 of the magnetic tape 110 is DC (direct current) demagnetized or AC (alternating current) demagnetized before data signal recording. Under these conditions, when the recording currents +Iw and −Iw are input to the input terminals 103 and 104, the recording current shown in the waveform diagram (c) in FIG. 4 flows to the head 101 and the region 111 is magnetized in the direction shown by the arrow C or D, as shown in the schematic view (b) in FIG. 4. That is, the region 111 becomes overwritten as the magnetized region 112 that has been magnetized in the direction shown by the arrow C and as the magnetized region 113 that has been magnetized in the direction shown by the arrow D.
Patent Documents 1 and 2, for example, disclose technology for recording data signals onto magnetic tapes. In Patent Document 1 (JP H8-30942A), a structure is disclosed that improves the output of servo signals by writing the servo signals by reverse magnetizing a magnetic recording medium after having maintained magnetization in one direction in a DC erase process. In addition, Patent Document 2 (JP S63-259805A) discloses a recording apparatus that, after DC erasure of the magnetic recording medium beforehand, adjusts the timing during magnetization inversion writing, in order to prevent waveform distortion when writing data signals.
However, using conventional structures, when recording signal data onto the magnetic tape 110, because the recording current +Iw and −Iw has to flow to the head 101, during signal data recording, the recording current continuously flows to the head 101. Consequently, a problem exists because the power consumed by the device increases.
In addition, by causing current to flow continuously to the head 101, the load on the head (especially, head chips used for writing) or to the entire circuitry increases, and the life span of the electronic components that form the head 101 or circuits is shortened.
In addition, because the head 101 is unitized with the head chip used for writing and the head chip used for reading (magnetic sensor type read head) that are arranged adjacent each other, due to magnetic field leakage to the head chip used for writing with increases in recording current to the head 101, a problem exists in that noise increases (crosstalk noise) for the head chip used for reading.
In addition, as shown in FIG. 3, because the circuit structure of the data recording apparatus is complicated, along with a cost increase, miniaturization of the entire apparatus is difficult.